The present invention relates to a cooling apparatus and a cooling system utilizing adsorbents.
One of conventional cooling apparatuses utilizing adsorbents is disclosed in Unexamined Japanese Patent Publication No. 5-115737.
In the cooling apparatus disclosed in this publication, a high-humidity air is brought into contact with an adsorbent to be turned into a low-humidity air, and the low-humidity air is humidified by a humidifier, thereby removing heat of vaporization of water from the low-humidity air. In this manner, the temperature of the low-humidity air is lowered and the humidity thereof is made high. The resulting low-temperature air is then utilized for cooling.
In such a cooling apparatus, however, humidification is compulsorily carried out for cooling air by means of the humidifier. Because of such compulsory humidification, it sometimes happens that a moisture content in the air discharged into a room goes beyond a saturated vapor amount, which results in generation of a mist. In these cases, the humidity of air inside the room is made excessively high, and amenity is thus lost in the room.
Also, the aforementioned cooling apparatus comprises a humidifier itself, a pipe arrangement for supplying water to the humidifier, and a feed water tank for storing water for humidification. This means that the entire cooling apparatus is made complicated in structure and large in size. Additionally, it is necessary to frequently resupply water into the feed water tank and, consequently, such management of water in the feed water tank is very bothersome.
The aforementioned trouble in the resupply of water into the feed water tank could be reduced by utilizing service water, ground water, or the like, which is supplied from a water supply system fixedly provided. However, on the premise that water supplied from such an immovable water supply system is utilized as water for humidification, the cooling apparatus should be disposed in a fixed position as well, which means that the cooling apparatus would not be usable, for example, as a cooling apparatus for automobile use.
The present invention was made to solve the aforementioned problems. More particularly, one object of the invention is to provide a cooling apparatus which is capable of cooling by humidification, without the necessity of compulsory humidification by means of a humidifier, the humidification being performed within a range in which a saturated vapor amount is not exceeded. Also, the other object of the invention is to provide a cooling apparatus which is capable of cooling by humidification, without utilizing water from a feed water tank with which resupply of water is required, or from an immovable water supply system.
In order to attain the aforementioned objects, according to a first aspect of the invention, there is provided a cooling apparatus comprising:
an adsorber in which moisture contained in air in a flow path is adsorbed by a first adsorbent;
a radiator in which heat of the air in the flow path is radiated out of the flow path via a heat conductive member;
a desorption cooler in which moisture is desorbed from a second adsorbent into the air in the flow path, thereby cooling the air in the flow path;
blast means for flowing the air through the flow path, said flow path running from an inlet of air, via the adsorber, the radiator and the desorption cooler, to an outlet of air;
outlet switching means for switching the outlet of air from/to an inside of a room to/from an outside thereof; and
heating means for heating the first adsorbent in the adsorber such that the moisture is desorbed from the first adsorbent.
In this first cooling apparatus, the absorber is a device where the air flowed thereinto is brought into contact with the first adsorbent and then flowed out thereof. A specific structure of the adsorber is not particularly restricted. For example, it may be composed of a case forming the flow path of the air, the case being filled with the first adsorbent. Alternatively, it may be composed of wall surfaces forming the flow path of the air, the first adsorbent being applied onto the wall surfaces. Otherwise, it may be composed of a case or wall surfaces forming the flow path of the air, the case or the wall surfaces itself/themselves being formed out of a composition containing the first adsorbent as a main component.
The radiator is a device where the air flowed thereinto is brought into contact with the heat conductive member and then flowed out thereof. The heat conductive member needs to be capable of removing heat from the air in the flow path and then transferring the heat to the outside of the flow path. As such a heat conductive member, not by way of restriction but by way of example, fins or a plate formed out of a metal having a high heat transfer coefficient (such as copper, aluminum, or any alloy containing these) may be used. In this case, heat can be removed from the air in the flow path by means of heat exchange between the air in the flow path and an outside air. Alternatively, a pipe arrangement may be provided using the metal having a high heat transfer coefficient to be used as the heat conductive member. In this case, heat can be removed from the air in the flow path by means of heat exchange between the air in the flow path and a cooling medium, such as cooling water or the like, flowing through the pipe arrangement.
The desorption cooler is a device where the air flowed thereinto is brought into contact with the second adsorbent and then flowed out thereof. As with the specific structure of the adsorber, the desorption cooler may be composed of a case forming the flow path of the air, the case being filled with the second adsorbent. Alternatively, it may be composed of wall surfaces forming the flow path of the air, the second adsorbent being applied onto the wall surfaces. Otherwise, it may be composed of a case or wall surfaces forming the flow path of the air, the case or the wall surfaces itself/themselves being formed out of a composition containing the second adsorbent as a main component. However, it is not necessary that the specific structure of the desorption cooler should be the same as that of the adsorber.
The blast means is provided to flow the air through the flow path running from the inlet of air to the outlet thereof and may be realized, for example, by disposing a blower, such as a motor fan or the like, in the flow path. Such a blower can be disposed in any position between the inlet of air and the outlet thereof, as long as the flow of air through the flow path from the inlet of air to the outlet thereof is permitted.
The outlet switching means is realized, for example, by disposing a damper, or the like, which is capable of selectively flowing the air through one of two courses of the fluid path.
The heating means can be any means that is capable of heating the first adsorbent in the adsorber. For example, if there is available an applicable heat source, such as waste heat generated by operation of a factory, solar heat or the like, means for introducing into the adsorber the heat obtained from such a heat source may be provided. In the case of the cooling apparatus for automobile use, means for introducing into the adsorber the heat generated from an automobile engine is also possible. If there is no such heat sources available, heat generating means, such as a heating wire, may be provided to generate heat utilizing electric power. In this case, the midnight power, which is less expensive, may be utilized.
According to the cooling apparatus having the aforementioned structure, by switching the outlet of air to the inside of the room by means of the outlet switching means, and by activating the blast means without activating the heating means, the air introduced from the inlet of air is flowed through the adsorber, the radiator, and the desorption cooler, and then discharged into the room. This operational status is hereinafter referred to as a cooling mode. As to the inlet of air, if cooling efficiency is only considered, it is desirable that the air should be introduced from the inside of the room; however, if ventilation is also taken into consideration, the air may be introduced from the outside of the room. Accordingly, any means may be provided for the inlet of air such that the air can be selectively introduced from either of the inside or outside of the room, or such that it can be introduced from both sides at the same time.
During the operation in the cooling mode, in the adsorber, moisture contained in the air is adsorbed by the first adsorbent, and the humidity of the air is thus lowered. Also, a heat of adsorption is generated by the adsorption of the moisture, and this heat of adsorption rises the temperature of the air. The resulting air of a lower humidity and a higher temperature is then flowed into the radiator. Subsequently, in the radiator, the heat of the air is radiated out of the flow path, and the temperature of the air is thus lowered. The resulting air of a lower temperature is then flowed into the desorption cooler. Subsequently, in the desorption cooler, moisture adsorbed by the second adsorbent during the operation in a reproducing mode (as described below) is desorbed from the second adsorbent. With this desorption of the moisture, heat is removed from the air with the result that the temperature of the air is further lowered. The resulting air of a further lowered temperature is then discharged into the room, thereby accomplishing cooling within the room.
Now, if this cooling apparatus is continuously operated in the aforementioned cooling mode, a quantity of the moisture that can be adsorbed by the first adsorbent in the adsorber is gradually reduced, while a quantity of the moisture that can be desorbed from the second adsorbent in the desorption cooler is gradually reduced. Here, by switching the outlet of air to the outside of the room by means of the outlet switching means, and by activating the heating means as well as the blast means, the air introduced from the inlet of air is flowed through the adsorber, the radiator and the desorption cooler to be discharged out of the room. This operational status is hereinafter referred to as the reproducing mode. As to the inlet of air, the air may be introduced from either or both of the inside or/and the outside of the room. However, if it is desired that the air in the room, which has already been cooled to some degree, should be prevented from being discharged outside, the air is preferably introduced from the outside of the room.
Switching between the cooling mode and the reproducing mode may be manually operated by a user, or may be automatically operated at a reserved time, or may be automatically operated on the basis of temperature or humidity conditions in the inside or outside of the room.
During the operation in the reproducing mode, in the adsorber, the first adsorbent is heated by the heating means, and with this heating, the moisture adsorbed by the first adsorbent during the operation in the cooling mode is desorbed therefrom. As a result, the first adsorbent is reproduced and its capacity for moisture absorption is recovered again. The air that has been risen in both temperature and humidity in the adsorber is then flowed into the radiator. Subsequently, in the radiator, the heat of the air is radiated out of the flow path, and the temperature of the air is thus lowered. With this lowering in temperature, the relative humidity of the air is further risen. The resulting air of a lower temperature and a higher humidity is then flowed into the desorption cooler. Subsequently, in the desorption cooler, moisture contained in the air is adsorbed by the second adsorbent, from which moisture has been desorbed during the operation in the cooling mode. As a result, the second adsorbent is saturated with the adsorbed moisture, and its capacity for desorption cooling is thus recovered. The air flowed out of the desorption cooler is then discharged out of the room.
As mentioned above, with this first cooling apparatus, air is cooled by the desorption of the moisture from the second adsorbent in the desorption cooler and, therefore, there is no possibility that a moisture content in the air discharged into the room might exceed a saturated vapor amount, and generation of a mist can thus be prevented, unlike the case with a conventional cooling apparatus in which humidification is compulsorily preformed by means of a humidifier for cooling air. Accordingly, the humidity of the air in the room is never made excessively high, and thus, amenity is not lost inside the room, compared to the case of humidification by means of a humidifier.
Also, since it is unnecessary to provide a humidifier itself, a pipe arrangement for supply of water to the humidifier, nor the like, the entire structure of the cooling apparatus can be made compact.
Furthermore, the moisture desorbed from the second adsorbent is the moisture collected from the air by the first adsorbent during the operation in the cooling mode and transferred to the second adsorbent during the operation in the reproducing mode and, therefore, provision of a feed water tank for storage of water for humidification, or use of a water supply system for supplying service water or ground water as water for humidification is not required. As a result, it is no longer necessary to take the trouble in resupply of water into the feed water tank. In addition, since the water supply system, which is immovably provided, is not necessary to be used, a cooling apparatus not to be located in a fixed position, for example, a cooling apparatus to be installed in an automobile, can be realized as well.
In this cooling apparatus, the air is blown, by the blast means, in the same direction in both of the cooling and reproducing modes. Accordingly, the blast means can be controlled more easily, compared to the case where switching control for directions in which the air is blown is required. Also, as to the means for switching courses of the flow path of the air, provision of at least the aforementioned outlet switching means suffices. Accordingly, the outlet switching means can be controlled more easily as well, compared to the case where a complicated switching control for the courses of the flow path is necessary to be performed by means of a lot of dampers or the like.
According to a second aspect of the invention, there is provided a cooling apparatus comprising:
a radiator-type adsorber in which moisture contained in air in a flow path is adsorbed by a first adsorbent and a heat of adsorption generated by the adsorption of the moisture is radiated out of the flow path via a heat conductive member;
a radiator in which heat of the air in the flow path is radiated out of the flow path via a heat conductive member;
a desorption cooler in which moisture is desorbed from a second adsorbent into the air in the flow path, thereby cooling the air in the flow path;
blast means for flowing the air through the flow path, said flow path running from an inlet of air, via the radiator-type adsorber, the radiator and the desorption cooler, to an outlet of air;
outlet switching means for switching the outlet of air from/to an inside of a room to/from an outside thereof; and
heating means for heating the first adsorbent in the adsorber such that the moisture is desorbed from the first adsorbent.
This second cooling apparatus is provided with the radiator-type adsorber, instead of the adsorber provided in the foregoing first cooling apparatus. In the radiator-type adsorber, moisture contained in the air in the flow path is adsorbed by the first adsorbent, which is also carried out in the adsorber in the foregoing first cooling apparatus. In addition, in the radiator-type adsorber, a heat of adsorption, which is generated by the adsorption of the moisture, is radiated out of the flow path via the heat conductive member, which is not carried out in the adsorber in the foregoing first cooling apparatus. As specific forms of the heat conductive member for use in the radiator-type adsorber, those of the heat conductive member for use in the radiator can arbitrarily be used. By adopting such a radiator-type adsorber, the first adsorbent becomes more difficult to rise in temperature, compared to the case of use of the adsorber in the foregoing first cooling apparatus.
The second cooling apparatus with the radiator-type absorber is also capable of operating in the aforementioned cooling mode. More particularly, as in the first cooling apparatus, by switching the outlet of air to the inside of the room by means of the outlet switching means, and by activating the blast means without activating the heating means, air cooling can be accomplished inside the room.
As aforementioned, the first adsorbent disposed in the radiator-type adsorber is more difficult to rise in temperature and, therefore, the adsorbability per unit quantity of the first adsorbent in the radiator-type adsorber is made higher than that of the first adsorbent disposed in the absorber in the first cooling apparatus. Accordingly, with the same quantity of the first adsorbent, the second cooling apparatus with the radiator-type adsorber can be operated in the cooling mode continuously longer than the first cooling apparatus with the adsorber. Otherwise, for continuous operations in the cooling mode for the same length of time, the second cooling apparatus with the radiator-type adsorber requires a smaller amount of the first adsorbent compared to the first cooling apparatus with the adsorber. In the latter case, the radiator-type adsorber can be made compact, thereby realizing miniaturization of the cooling apparatus itself.
Also, the second cooling apparatus with the radiator-type adsorber is capable of operating in the aforementioned reproducing mode as well. More particularly, as in the first cooling apparatus, by switching the outlet of air to the outside of the room by means of the outlet switching means, and by activating the heating means as well as the blast means, the adsorbability of the first adsorbent can be recovered and the second adsorbent can be saturated with the adsorbed moisture.
According to a third aspect of the invention, there is provided a cooling apparatus comprising:
a radiator-type adsorber in which moisture contained in air in a flow path is adsorbed by a first adsorbent and a heat of adsorption generated by the adsorption of the moisture is radiated out of the flow path via a heat conductive member;
a desorption cooler in which moisture is desorbed from a second adsorbent into the air in the flow path, thereby cooling the air in the flow path;
blast means for flowing the air through the flow path, said flow path running from an inlet of air, via the radiator-type adsorber and the desorption cooler, to an outlet of air;
outlet switching means for switching the outlet of air from/to an inside of a room to/from an outside thereof; and
heating means for heating the first adsorbent in the adsorber such that the moisture is desorbed from the first adsorbent.
This third cooling apparatus has the same structure as the foregoing second cooling apparatus, except that the radiator is removed therefrom.
The third cooling apparatus having no radiator is also capable of operating in the aforementioned cooling mode. More particularly, as in the first and second cooling apparatuses, by switching the outlet of air to the inside of the room by means of the outlet switching means, and by activating the blast means without activating the heating means, air cooling can be accomplished inside the room.
Differently from the foregoing first and second cooling apparatuses, there is no radiator provided in the third cooling apparatus. However, since the third cooling apparatus has the radiator-type adsorber which is the same as that of the second cooling apparatus, the heat of adsorption can be outwardly released from the radiator-type adsorber. In other words, the third cooling apparatus can be realized on the premise that the radiator-type adsorber has a sufficiently high heat radiating capacity. By removing the radiator, the entire structure of the cooling apparatus can be made more simple.
Also, the third cooling apparatus having no radiator is capable of operating in the aforementioned reproducing mode as well. More particularly, as in the first and second cooling apparatuses, by switching the outlet of air to the outside of the room by means of the outlet switching means, and by activating the heating means as well as the blast means, the adsorbability of the first adsorbent can be recovered and the second adsorbent can be saturated with the adsorbed moisture.
According to a fourth aspect of the invention, in addition to the structure of any of the foregoing first through third cooling apparatuses, the cooling apparatus may further comprise at least one auxiliary cooling mechanism having:
flow diverting means for diverting part of the air flowing through a main course of the flow path to a side course thereof;
an auxiliary desorption cooler in which moisture is desorbed from the second adsorbent into the air flowing through the side course of the flow path, thereby cooling the air in the side course of the flow path; and
a heat exchanger by which heat exchange is allowed between the air in the main course of the flow path and the air in the side course thereof, which has been cooled by the auxiliary desorption cooler, thereby cooling the air in the main course of the flow path,
the at least one auxiliary cooling mechanism being disposed in an upper course of the flow path relative to the desorption cooler such that the air cooled by passing through the main course of the flow path in the at least one auxiliary cooling mechanism is subsequently flowed into the desorption cooler.
In this fourth cooling apparatus, the auxiliary cooling mechanism is provided in the upper course of the flow path relative to the desorption cooler, more particularly, it is provided in the flow path between the radiator and the desorption cooler in the case of the structure of the first or second cooling apparatus, and in the flow path between the radiator-type adsorber and the desorption cooler in the case of the structure of the third cooling apparatus.
Also, one or more auxiliary cooling mechanisms may be provided, and each of the auxiliary cooling mechanisms is composed of the flow diverting means, the auxiliary desorption cooler and the heat exchanger. When the fourth cooling apparatus is operated in the cooling mode, the air diverted and introduced, by the flow diverting means, into the side course of the flow path is a low-humidity air that has already passed through the adsorber. Accordingly, once the low-humidity air is flowed into the auxiliary desorption cooler, moisture adsorbed by the second adsorbent during the operation in the reproducing mode is desorbed therefrom. With this desorption of the moisture, heat is removed from the air, and thus, the temperature of the air in the side course of the flow path is lowered. Subsequently, in the heat exchanger, heat exchange is allowed between the air in the main course of the flow path and the air in the side course of the flow path, which has been cooled by the auxiliary desorption cooler, thereby cooling the air in the main course of the flow path. As a result, the air flowing through the main course of the flow path has an absolute humdity equal to that of the air having passed through the adsorber and a temperature lower than that of the air having passed through the adsorber only. Accordingly, by flowing the resulting air through the desorption cooler, the air finally discharged into the room can further be cooled.
On the other hand, when the fourth cooling apparatus is operated in the reproducing mode, the air diverted and introduced, by the flow diverting means, into the side course of the flow path is a high-humidity air that has been humidified with the reproduction of the first adsorbent in the adsorber. Accordingly, once the high-humidity air is flowed into the auxiliary desorption cooler, moisture is adsorbed by the second adsorbent. As a result, the second adsorbent is saturated with the adsorbed moisture and the desorption cooling capacity of the second adsorbent is thus recovered.
In cases where two or more auxiliary cooling mechanisms are provided, they are usually arranged in series such that the air having passed through the main course of the flow path in the first auxiliary cooling mechanism subsequently passes through the main courses of the flow path in the second and, if any, further auxiliary cooling mechanisms in turn. By this arrangement, the air can be cooled in stages by passing through each of the plurality of auxiliary cooling mechanisms. It is also possible to arrange two or more auxiliary cooling mechanisms in parallel, more particularly, to arrange them on each of two or more branch flow paths, the branch flow paths being separated in midstream of the entire flow path and merging into each other again. In this case, the air introduced into each of the branch flow paths only passes through one of the plurality of auxiliary cooling mechanisms and, therefore, the air is not cooled in stages, unlike the case where the plurality of auxiliary cooling mechanisms are arranged in series.
According to a fifth aspect of the invention, there is provided a cooling apparatus in which:
the first adsorbent has a 10% or more difference between its moisture absorption percentage at 0% relative humidity and that at 50% relative humidity; and
the second adsorbent has a 10% or more difference between its moisture absorption percentage at 60% relative humidity and that at 100% relative humidity.
In this fifth cooling apparatus, an adsorbent having a difference of 10% or more between its moisture absorption percentage at a relative humidity of 0% and that at a relative humidity of 50% is used as the first adsorbent. As a representative example of such an adsorbent, a silica gel of a micro-pore type having an average pore size of approximately 2 to 5 nm (for example, A-type silica gel) can be given. Also, an adsorbent having a difference of 10% or more between its moisture absorption percentage at a relative humidity of 60% and that at a relative humidity of 100% is used as the second adsorbent. As a representative example of such an adsorbent, a silica gel of a mezzo-pore type having an average pore size of approximately 5 to 10 nm (for example, B-type silica gel) can be given.
In the fifth cooling apparatus, the first adsorbent has a high adsorbability in a relatively low-humidity atmosphere and, therefore, the first adsorbent is preferably used to obtain a low-humidity air in the cooling mode. On the contrary, the second adsorbent is capable of adsorbing a large quantity of moisture in a relatively high-humidity atmosphere. In addition, the second adsorbent has a tendency to relatively easily desorb the moisture adsorbed thereonto, compared to the aforementioned first adsorbent. Accordingly, the second adsorbent is preferably used to humidify the air in the cooling mode.
Now, each of the foregoing cooling apparatuses can recover its cooling capacity through the operation in the reproducing mode, following the operation in the cooling mode. However, there is a limit to the cooling performance by each of the foregoing cooling apparatuses, since they can provide no cooling effect while being operated in the reproducing mode.
Such a limit is not a serious problem if operating hours in the reproducing mode can be sufficiently secured following continuous operating hours in the cooling mode, especially, in cases where, for example, in a factory or the like, the cooling apparatus is operated in the cooling mode during the day, and operated in the reproducing mode during the night.
However, in cases where even a bare minimum of operating hours in the reproducing mode can not be secured following the continuous operating hours in the cooling mode, a time during which the cooling apparatus is capable of continuously operating in the cooling mode next time is shortened and, therefore, the cooling capacity of the cooling apparatus is deteriorated in a short period of time.
In order to solve the aforementioned problem, according to a sixth aspect of the invention, there is provided a cooling system comprising a plurality of cooling apparatuses as mentioned above, wherein
each of the plurality of cooling apparatuses is operated in two operational modes; one of the two operational modes being a cooling mode in which the outlet of air is switched to the inside of the room by means of the outlet switching means and the blast means is activated while the heating means is not activated; the other being a reproducing mode in which the outlet of air is switched to the outside of the room by means of the outlet switching means and the heating means as well as the blast means are activated; and
the two operational modes are alternately repeated by each of the plurality of cooling apparatuses, while control is made in such a manner that at least one of the plurality of cooling apparatuses is operated in the cooling mode.
In this cooling system, the plurality of cooling apparatuses are respectively operated in the two operational modes repeatedly by turns. In addition, control is always made in such a manner that at least one of the plurality of cooling apparatuses is operated in the cooling mode. As a result, as soon as the cooling capacity of one of the plurality of cooling apparatuses falls below a necessary level, another cooling apparatus can be started to operate in the cooling mode. In this manner, a continuous cooling of air is made possible.
By adopting this cooling system, cooling can be performed without problems even in cases where the operating hours in the cooling mode need to be longer than those in the reproducing mode, especially, even in cases where a full-time operation in the cooling mode might be required.